Wolfgang Doster

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The cytoplasm of red blood cells is congested with the oxygen storage protein hemoglobin occupying a quarter of the cell volume. The high protein concentration leads to a reduced mobility; the self-diffusion coefficient of hemoglobin in blood cells is six times lower than in dilute solution. This effect is generally assigned to excluded volume effects in(More)
Polarization analysis was used to separate experimentally the coherent and spin-incoherent nuclear static scattering functions, from a representative set of samples of interest for protein studies. This method had so far limited application in the study of amorphous materials, despite the relevance of the information that it provides. It allows, for(More)
The statistical properties of fast protein-water motions are analyzed by dynamic neutron scattering experiments. Using isotopic exchange, one probes either protein or water hydrogen displacements. A moment analysis of the scattering function in the time domain yields model-independent information such as time-resolved mean square displacements and the(More)
The dynamics of hydrated proteins and of protein crystals can be studied within a wide temperature range, since the water of hydration does not crystallize at low temperature. Instead it turns into an amorphous glassy state below 200 K. Extending the temperature range facilitates the spectral separation of different molecular processes. The conformational(More)
Reversible and irreversible states of pressure-dissociated casein micelles were studied by in situ light scattering techniques and ex situ atomic force microscopy. AFM experiments performed at ambient pressure reveal heterogeneities across the micelle, suggesting a sub-structure on a 20 nm scale. At pressures between 50 and 250 MPa, the native micelles(More)
Caseins form heterogeneous micelles composed of three types of disordered protein chains (α, β, κ), which include protein-bound calcium phosphate particles. We probe the stability limits of the micelle by applying hydrostatic pressure. The resulting changes of the size distribution and the average molecular weight are recorded in situ with static and(More)